Design and Architecture

Paulo S X Soares6-Jun-13 3:06

Paulo S X Soares

6-Jun-13 3:06

hmmm.. It can be an option.

Abhinav S5-Jun-13 22:17

Abhinav S

5-Jun-13 22:17

Next time, you can post in the PHP forum.
It might get more people to answer your question.

Apps - Color Analyzer | Arctic | XKCD | Sound Meter | Speed Dial

Paulo S X Soares6-Jun-13 2:58

Paulo S X Soares

6-Jun-13 2:58

I was doubted about the right place to post. This question is not specifically about PHP. I know how to do it. PHP is given just as an example. My doubt is about the best method, whatever language we could use.

jschell6-Jun-13 10:15

6-Jun-13 10:15

Paulo S X Soares wrote:
A cons: duplicated code to retrieve same data

Whatever you mean by that it isn't happening unless you are doing something wrong.

Paulo S X Soares7-Jun-13 5:22

Paulo S X Soares

7-Jun-13 5:22

Let's see an example.
I already have the class clsUser. The class has the GetData method, used to retrieve data and fill an $User instance.

$User=new clsUser;
$Result=$User->GetData($ID);

In GetData method there is a query like "select ID,Name,Type,etc... from Users where ID=".$ID.
In other point of the application, I need a list ou users for some purpose. I use a query like "select ID,Name,Type,etc... from Users where <whatever>". See that the fields list is the same in both queries. That's what I call duplicated code.

jschell10-Jun-13 9:02

Help on designing DB/ Web Service

10-Jun-13 9:02

Paulo S X Soares wrote:
n other point of the application, ...That's what I call duplicated code.

The you should be using a database layer with appropriate idioms - which would avoid that.

DavJes4-Jun-13 7:49

DavJes

4-Jun-13 7:49

Hi,

I have good development experience, have been in developing projects more than 8 years. But I had been asked to design complete end to end software for a project. It involves designing DB, WCF Server, communication protocols(like xml formats, schema ..etc) . As I am new to design the software, need help on quickly learning on designing the product like DB design and system design. Please help me to learn those aspects quickly to do build software. Please suggest me how to start with , like good books/links/tutorials. Especially on designing DB and web service protocols and communications. I don't have much time to learn though. So your suggestions/guidance will be great help.

Thanks in advance.

jschell4-Jun-13 8:54

4-Jun-13 8:54

DavJes wrote:
Please help me to learn those aspects quickly

It depends on what you mean by "quickly" but in general that isn't going to happen.

If the project is smaller then it probably isn't going to matter but a larger multi-application system isn't going to be designed quickly even if you already knew how to do it.

Myself I used Visio and Word to create my design documents. Visio for diagrams and Word for the actual design.

DavJes wrote:
Especially on designing DB

Depends on the data. If you know what the data is and have some experience with database tables then all you need to do for the design is document each table and the values that go in each. You don't need to specify column sizes in the design unless there are requirements that specifically indicate sizes. A diagram with some comments following on each table is sufficient.

DavJes wrote:
web service protocols and communications.

This is either trivial or very difficult depending on what the system does and what the methods are supposed to do. But in general you can specify each method is pseudo code and document input and output values. Documenting every method and variation probably isn't needed.

Eddy Vluggen4-Jun-13 8:55

Eddy Vluggen

4-Jun-13 8:55

For database-design, I'll always recommend Normalizing upto BCNF. For webservices, I'd recommend the book "SOA patterns" from Manning. As the title says, it focuses on (design) patterns; using predefined code-structures that can be easily communicated about makes 'architecting' a bit easier. http://www.joelonsoftware.com/[^] has some nice reads touching the topic.

DavJes wrote:
I don't have much time to learn though

Learn a bit each day; no project starts with a 'perfect' architecture.

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]

DavJes9-Jun-13 7:03

DavJes

9-Jun-13 7:03

hey thanks for the info. Please just guide me to learn how to do DB design and webservice architecture, I appreciate your help. Any good books, or links which can help. I understand it can't be learnt overnight, but at-least i will make it a point to learn faster.

thanks

Transactional MSMQ & firewall

Eddy Vluggen10-Jun-13 3:26

Eddy Vluggen

10-Jun-13 3:26

DavJes wrote:
Please just guide me to learn how to do DB design and webservice architecture

Can't give more pointers on webservices than the book I mentioned. I've listed some resources on database-normalization, which would be the preferred design IMHO.

MSDN[^], explains up to rule #6
MSDN[^], tips
Wikipedia[^], with examples and explanation. (Links halfway details on every step)
SqlMag[^] has a nice introduction on the topic, as well as a link that explains when normalization should be skipped.

Personally, I don't go all the way, just upto BCNF. It's boring and tedious stuff to learn and apply, but I wouldn't recommend it if the advantages don't outweigh the disadvantages; the result will be more confidence in the model used, fewer design-errors, and within a few tables you'll be normalizing your structures without effort.

The reason I recommended Mannings' SOA patterns[^] is because it focuses on the most-used patterns; a pattern is a proven and reusable solution, and that's always a nice thing to have in any architecture. I also recommend it because I read and enjoyed it myself Smile | :)

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]

John Padgett27-May-13 22:35

John Padgett

27-May-13 22:35

Server A hosts the MSMQ queues and is in a DMZ.
Server B is within the corporate network and hosts the workflow services that monitor the MSMQ queues on Server A.

For transactional message processing DTC is used and the article http://support.microsoft.com/kb/918331 says that ports 135 and the dynamic port allocation need to be opened in both ways on the firewall to allow this process to work.

Does this mean that both inbound and outbound requests need to be allowed through the firewall i.e. an inbound request can be made from Server A to Server B that was not initiated from Server B? The Infrastructure team are not keen on allowing inbound access to the corporate network containing Server B from the DMZ. In an ideal world an outbound request would be initiated from Server B and the traffic could flow in both directions once this connection was made but any inbound requests initiated from Server A to Server B would not be allowed.

Sorry my knowledge of firewalls and how the traffic works between machines and the firewall is not too hot so the explanation might be a bit off or if this is the wrong place for the question.

Thanks

John

Re: Transactional MSMQ & firewall

jschell28-May-13 9:31

SOA and exposing a program from the 80s

28-May-13 9:31

John Padgett wrote:
Server A hosts the MSMQ queues and is in a DMZ.

You are in for a world of hurt. Traffic flow MSMQ to MSMQ is very complex and thus very hard to figure out even when one tracks down the documentation.

John Padgett wrote:
an inbound request can be made from Server A to Server B that was not initiated
from Server B?

Of course not.

John Padgett wrote:
Does this mean that both inbound and outbound requests need to be allowed
through the firewall

I supect you would need to test it. I wouldn't suppose that a post from A to B would require outbound but certainly a post that originates on B would.

darklies17-May-13 19:37

darklies

17-May-13 19:37

Hi,
I have been given the task of exposing our internal software to the outside world.

the software was written in a proprietory language in the early 80s. The software has a hook that you can use to
instantiate forms in the program just as if you were
a real user typing into them.

This hook is abstracted to the point that it offers
1 class to instantiate any of the available forms(300+)
1 function to perform any type of search on the form (it takes one function parameter, an array of objects)
1 function to perform any type of action on the form (it takes one function parameter, an array of objects)
etc...

So I have several concerns (I have been reading a lot, but have little practical experience)
1. Does anyone know of a good resource that would help me out on designing the interface/choosing how to expose?

2. The above hook is simple, however, it would be a nightmare to consume as is. I feel that I have to remove some of the abstraction.
The forms are a 1:1 with database tables,
would I create a 1:1 class:form ?
OR suggestions...?

3. There is no security/authentication built in to this hook, Can someone point me towards a resource on this as well.

Re: SOA and exposing a program from the 80s

jschell20-May-13 11:09

Re: SOA and exposing a program from the 80s

20-May-13 11:09

Realistically it isn't possible to answer this.

If one one knew the forms then one might come up with a better way to organize them.
If not them someone else would need to provide that info.
We can't answer that.
Without that information it is hard to say what should be done.
Obviously the simplest representation is to just to provide each form. And the consumer of these might find that form the easiest to use as well.

Since there appears to be a direct one to one correspondence code generation is the easiest way to quickly get them up.

User management is harder since, again there are no requirements. For starters if you have users who creates/manages them? Do all users have complete access to everything? What sort of users will use it - for example if you are going to allow complete trust with fixed customers then VPN is all you need.

darklie22-May-13 16:41

darklie

22-May-13 16:41

thanks for your response.

In regards to your questions about user management.

*if you have users, who creates/manages them?
Administrators create and manage users

*Do all users have complete access to everything?
No access is restricted based on products.
The hook available to us does not force a user to log in.
All functions and data are available through the hook.
You can run through the program anonymously using the hook.

*What sort of users will use it?
All users are customers.
It will be available on the internet.

my biggest fear is that if our internet server gets compromised the hacker has an access point to our software and all data without restriction.
I am looking for a way to use the hook available and mitigate/prevent damage, if our gateway server gets hacked.

Perhaps you can point me to a resource that will help/teach me to implement security measures?

jj

Re: SOA and exposing a program from the 80s

jschell24-May-13 12:26

Language features required (or useful) for numerical computing

24-May-13 12:26

jdjacobucci wrote:
Administrators create and manage users

Where do those come from? Has the business committed to tasking someone with that?

jdjacobucci wrote:
No access is restricted based on products.

Can a customer that has access to X product set manager their own users or does your company need to do that? The answer to that impacts the architecture, design and implementation.

jdjacobucci wrote:
It will be available on the internet.

Then you must concern yourself with security.

jdjacobucci wrote:
if our gateway server gets hacked.

Provide a gateway. Your application talks to the existing product. The existing product is NOT exposed to the internet. Actually you should insure that the network access though that portal should be a via a firewall that only allows access from your application box.

harold aptroot15-May-13 3:49

harold aptroot

15-May-13 3:49

Most languages don't expose features that you (could) need, such as the double-extended format, rounding modes, and things like the "inexact result" flag, that are in the IEEE 754 standard.

So, I guess what I'm asking is, am I even on the right track here?

I've identified some things as necessary or useful:
- the optimizer will not mess with associativity or distributivity or identities such as "a - a == 0" that do not generally hold. Very important. There are compilers that break this rule even if you don't enable something like "-ffast-math", especially things like GPU Shader compilers, destroying many algorithms.
- lexically scoped* rounding modes. Could be done as global state, but that has two effects: 1) you can run the same function several times with different rounding modes, which is a good (not perfect) test for numerically bad code, and 2) it makes reasoning about the code very hard, since you can't make any assumptions about the rounding mode without analyzing all possible call trees.
- lexically scoped control for "flush to zero" and "denormals are zero". Less important, but allows optimization where needed without having to enable it globally.
- support for reading/clearing the sticky flags. Not sure what the syntax should look like to make that nice, but it's probably not super important to make it nice.

And there are some things I'm not too sure about:
- introduce the internal types "auto_double" and "auto_wider_double". Operations on floating point types would automatically upcast once to a wider type. The internal types are to avoid doing (float + float) + (float + float) in overly wide precision.

       |  float | double | x 
float  | double | double | x
double | double | x      | x
x      | x      | x      | x

But what should x be? There's double-extended, but that can only be implemented with old-school x87 instructions. Double-double arithmetic could be done in xmm registers, and isn't as slow as it seems. But not as fast by far as using the old-school FPU, which suffers almost no penalty for double-extended precision (division, square root, saving and loading is about all that's affected), and, IIRC, double-double arithmetic doesn't always round the way we'd like it to.
And should this be a feature at all? The programmer could just as well do it himself by upcasting - and then the programmer could choose not to do that, without necessitating yet an other lexically scoped mode ("no widening", see below). It would save the average noob's ass once in a while, but history shows that languages oriented at noob often end up so horrifying that only noobs dare use them.
- should double-double (this is not the binary128 type by the way, but an uninterpreted sum of 2 doubles) and quad-double arithmetic be built-in and exposed though types? It would be useful, but not all that often, and could be implemented in code. It's not clear whether the advantages outweigh the costs.

* what should this even look like? Something like this?

float(round nearest) // default mode, so this changes nothing
{
    // do some arithmetic
}

// round to +Infinity, denormals are zero, flush to zero and
// don't automatically widen types
float_mode(round up, daz, ftz, no widening)
{
    // maybe that whole auto-widening was over the top
}

Other ideas? And I'm not too sure what the keyword should be.

There's probably a ton of things I'm missing here. I'm not even a numerical analyst, not even close. I know just enough about floating point to know that I don't know what I'm doing.

PS: is this topical in this forum?

Re: Language features required (or useful) for numerical computing

jschell15-May-13 8:31